Field of the Invention
This invention relates in general to dispensers for pasty material and in particular to a new and useful paste dispenser which includes front and rear relatively movable tubular dispensing portions which are telescopically interengaged and include both a pasty material dispenser reservoir and a striping material dispensing reservoir which are interconnected in a discharge orifice.
The present invention pertains in particular to a paste dispenser with a dispensing pump for discharging metered amounts of substances of low viscosity, especially pasty substances, such as toothpaste, ointments, and the like. Such a device includes a bottle-like or can-like paste container, having bellows made of an elastic material arranged between two housing parts made of a dimensionally stable material such as plastic. The bellows establishes communication between housing parts which engage with one another telescopically in the axial direction and can be moved relative to one another between two stroke limiting paths and can be returned by axial return resilient forces. One of the housing parts is provided with a tubular discharge orifice which shapes a strand of paste. The discharge orifice communicates with an annular canal which is formed by two radially spaced apart tube sections on a housing part which are arranged concentrically to one another and coaxially to the axis of the bellows. The tube sections are open only at their respective end faces and the inner tube section is surrounded by a radially elastic, sleeve-like annular wall section of the bellows in the form of a valve seat. The annular wall section joins a wall section of the bellows which is in contact with the inner surface of the outer tube section in a sealing fashion. The second housing part is provided with a paste reservoir.
To squeeze paste out of the paste container through the discharge orifice, most of the prior-art paste dispensers are provided either with a displacing plunger in conjunction with a tracking plunger or with a thrust plunger, and the displacing plunger or the thrust plunger is gradually displaced in the direction of discharge by a pushbutton-like or lever-like, manually operated actuating member within the container. Due to the use of a displacing plunger in conjunction with a tracking plunger or of a thrust plunger, which is actuated by means of a pushrod via a guiding locking mechanism, it is possible to eliminate the use of pump valves in such paste dispensers. As a result, such paste dispensers can be manufactured relatively simply and inexpensively as described in West German Offenlegungsschrift No. 35,07,355, DE-OS West German Offenlegungsschrift No. 33,04,926, U.S. Pat. Nos. 4,120,431, 3,255,935, and British Patent No. 2,172,664 A.
In such paste dispensers, an additional striping paste of a different color can be added in a relatively simple manner in the form of a stripe to the strand of paste passing through the discharge orifice. It is only necessary to provide--in the area in which the discharge duct opens into the container--an annular wall, around which the striping paste is arranged, and to provide this annular wall with radial holes, through which the striping paste is introduced in the form of thin stripes into the discharge duct and consequently into the actual strand of paste.
In a paste dispenser of the type described here, in which bellows are arranged as a pumping member between the reservoir containing the medium to be dispensed and the discharge orifice, the striping paste cannot be added in the form described to the strand of paste, because the discharge orifice or its discharge duct, in which the strand of paste is shaped, does not reach into the paste reservoir.